Sealing of pressure vessels



June 14, 1966 E. c. RUST, JR 3,255,616

SEALING 0F PRESSURE VESSELS Filed Jan. 20, 1964 4 Sheets-Sheet 3 INVENTOR. EDGAR C. [Pl/57:1?-

ATTORNEYS.

June 14, 1966 E. c. RUST, JR

SEALING OF PRESSURE VESSELS 4 Sheets-Sheet 4 Filed Jan 20, 1964 1 N VENTOR. EDGAR c l/51,14

ff V a I A r :ORNE Y3.

pressure vessel.

United States Patent 3,255,616 SEALING 0F PRESSURE VESSELS Edgar C. Rust, Jr., North Adams, Mass., assignor to Crompton & Knowles Corporation, Worcester, Mass., a corporation of Massachusetts Filed Jan. 20, 1964, Ser. No. 338,868 3 Claims. (Cl. 68-5) This invention relates to pressure seals and, more especially, to an improved pressure seal for preventing the escapement of relatively high pressure from within a pressure tank or vessel at the points at which web or strand material is introduced into and/or withdrawn from the pressure tank or vessel. The present invention shall be hereinafter described as though it involves the processing of web material or fabric although it should be distinctly understood that the principles of the present invention apply to the processing of single strands or a plurality of strands or the processing of any type of material wherein it-is desirable to maintain a high pressure within a vessel and toprevent the escapement of the same when the material enters and leaves the vessel.

In treating textile material for the purpose of dyeing, desizing, boiling off, decatizing and other processes, it is often desirable to pass the impregnated fabric through a For this purpose, it has been proposed heretofore to provide at both the web inlet and the web outlet of the pressure vessel, a pressure seal comprising a housing containing a pair of opposed pressure sealing rollers which are positively driven and engage the opposite sides of the web to feed it into or from the vessel, these rollers being urged by the sealed pressure against fixed bearing plates in the housing to complete the seal. One of these rollers has a periphery which is yieldable locally against the sealed fluid pressure in the housing and thereby accommodate irregularities or variations in the web thickness.

It has been found, however, that such pressure seals as constructed heretofore are not entirely satisfactory for various reasons, among which are their failure to maintain an adequate seal while accommodating variations in the thickness of the *web, particularly at high speeds, and their failure to provide proper thermal conditions and lubrication within the housing of theseal.

The principal object of the present invention is to provide a pressure seal which overcomes the above-noted difficulties.

A pressure seal made according to the invention comprises a housing forming a chamber having two openings for passage of the web, the first opening communicating with .atmosphere while the second opening connects the chamber to the interior of the pressure vessel. One of these two openings serves as the web inlet to the housing chamber and the other serves as the web outlet from the chamber, depending upon whether the pressure seal is applied to the web inlet or the web outlet of the pressure vessel. Two roll seats are fixed in the housing chamber and extend along opposite sides, respectively, of the first opening (the one leading to atmosphere). A pair of rolls seated on the respective seats extend in substantially parallel relation to each other in position to receive the web between the rolls, one of the seated rolls being positioned to engage its periphery with one side of the web as it passes through the housing chamber. A yieldable roll in the chamber extends substantially parallel to the seated rolls and straddles them in position to have the periphery of the yieldable roll urged against the peripheries of the seated rolls by the sealed fluid pressure in the chamber, that is, the pressure which communicates from the pressure vessel through the second opening of the housing chamber. Thus, the yieldable roll is adapted to press the web against said one seated roll and accommodate varia- 3,255,616 Patented June 14, 1966 ice .tions in the web thickness while coacting with the straddled seated rolls to maintain a pressure seal between the two chamber openings through which the web passes;

In one embodiment of the invention, means are provided for driving the seated rolls in the same direction to advance the web toward or away from the pressure vessel, again depending upon whether the pressure seal is applied to the web inlet or the web outlet of that vessel. Also, the housing contains heating passages for a heating medium which are closed from the housing chamber and extending generally parallel to the rolls at opposite sides of the inlet and outlet; and at least one of the seated rolls is hollow to provide a cooling passage extending lengthwise of the roll and through which a cooling liquid is circulated.

The preferred construction comprises hollow trunnions extending from the ends of each hollow seated roll and communicating with the interior of the hollow roll. The trunnions project through openings in the end walls of the housing, and means are provided for sealing each of these openings around the corresponding trunnion. Each hollow trunnion extends from the corresponding sealing means into a sub-housing having a sealed chamber communicating with the interior of the trunnion. A cooling liquid supply pipe leads to the sealed chamber of one sub housing, and a cooling liquid discharge pipe leads from the sealed chamber of the other sub-housing, whereby the cooling liquid is circulated through the hollow roll.

- For a better understanding of the invention, reference may be had to the following detailed description in conjunction with the accompanying drawings, in which:

FIG. 1 is a plan view of a preferred form of the inven tion, with part of the seal housing broken away;

FIG. 2 is an enlarged sectional view on line 22 in FIG. 1;

FIG. 3 is an enlarged end view of the apparatus shown in FIG. 1, with the housing end plate, the trunnion sealing means and the sub-housing removed;

FIG. 4 is a plan view of an end portion of one of the hollow rolls, the corresponding sealing means and subhousing being shown in section;

FIG. 5 is a sectional view on line 55 in FIG. 4; and

FIG. 6 is a sectional view on line 66 in FIG. 1, the section being enlarged to thescale of FIGS. 4 and 5.

Referring to the drawings, the reference numeral 10 designates a pressure tank or vessel in which the fabric or other material is to be treated under pressure. For convenience, the. material to be treated will be referred to hereinafter as a web, although the material may take other forms.

For illustrative purposes, the pressure seal will be described as applied to the web inlet of the pressure vessel 10.

In its passage to the pressure vessel 10, the web passes through a pressure seal indicated generally at 11. As shown particularly in FIG. 2, the pressure seal 11 comprises a housing having a main body 12 and a cover plate 13 defining a chamber 14. The cover plate 13 is removably secured to the main body 12 of the housing by machine screws 15 and is provided with external reinforcing fins 13a extending transversely of the housing. A shield -16 of heat-insulating material is releasably secured to the housing body 12 between end flanges 17 and 18 of the cover plate 13.

The opposite ends of housing chamber 14 are closed by end plates 1'9 and 20 bolted to the housing body 12 v and the end flanges 17-18.

with an opening 23 extending lengthwise of the housing and forming an outlet leading from chamber 14 to an inlet passage 24 of the pressure vessel, the housing body 12 being removably secured to the pressure vessel by any suitable means such as machine screws 32 (FIG. 2). Roll seats 37 and 38 in chamber 14 are secured to housing body 12 at opposite sides of inlet 22. These seats are made of wear-resistant material such as Teflon and, as shown, have dovetailed connections with housing body 12 so that the seats may be slid lengthwise from the body to permit replacement of the seats.

The housing body 12 is also provided with longitudinal heating passages 26 and 27 located at opposite sides of inlet 22 and below the seats 37 and 38, respectively. The passages 26 and 27 are closed at their opposite ends by plugs 26a and 27a, respectively, fitted in these passages and welded or otherwise secured to body 12. Above the outlet 23, the housing body 12 is provided with another longitudinal heating passage 28 closed at its opposite ends by similar plugs 28a.

Each end portion of the housing is provided with passages 30a and 30b leading to a pipe 30 for discharging condensate from the sealed part of chamber 14. Each end portion of the housing is also provided with a steam condensate port 31a leading from passage 26 to a condensate discharge pipe 31 and with a port a through which steam or other heating fluid is supplied to passage 27. In each of its end portions, the housing has a passage 33 interconnecting the main passages 26 and 27 and a passage 34 interconnecting the main passages 27 and 28. Thus, all three heating passages 26, 27 and 28 are interconnected at their ends, and they can be supplied with heating fluid through ports 35a, the condensate being discharged through ports 3111. In this way, the housing body 12 is adapted to be maintained at a predetermined elevated temperature through heating passages which are closed from the chamber 14 and extend generally parallel to the roll seats 37-38.

Pipes 30 and 31 are provided with conventional steam traps (not shown) for allowing discharge of condensate while avoiding loss of pressure in chamber 14 and passages 26-27-28.

Rolls 39 and 40 are seated on the seats 37 and 38, respectively, and extend in parallel relation lengthwise of housings 12-13 at opposite sides of inlet 22. A yieldable roll 41 in chamber 14 extends parallel to the seated rolls 39-40 and straddles them from above (FIG. 2). At each end, the rolls 39, 4t) and 41 make sealing contact with a sheet of Teflon or other wear-resistant sealing material applied to the adjacent face of the corresponding end plate 19 or 20. Thus, .as shown in FIG. 4, one end of roll 39 bears against a sheet 20a on the adjacent face of end plate 20, this sheet also serving as a gasket between plate 20 and the adjacent ends of housing members 12 and 13.

As shown in FIG. 2, the web F to be treated in pressure vessel 10 passes upwardly through housing inlet 22, through the clearance space between rolls 39 and 40 at opposite sides of the inlet, and thence through the nip between rolls 40 and 41 into chamber 14, from which it passes through outlet 23 into the pressure vessel 10; the web being drawn through this vessel in any suitable manner, as by draw rolls (not shown) at its outlet end. The pressure in vessel 10 is communicated to housing chamber 14 through the chamber outlet 23 and acts to force the roll 41 against the straddled rolls 39 and 40, which in turn are pressed against their respective seats 37 and 38. Thus, a good seal is maintained between rolls 39 and 41 at their interengaging peripheries and between rolls 40 and 41 at their nip through which the web F is drawn.

The upper roll 41 is supported on the lower rolls 39-40 and is opposed at its ends by the sheet material (such as 20a) on the end plates 19 and 20. There is sutficient clearanceat the ends of roll 41 to allow it to rotate and move vertically and horizontally with freedom, while avoiding objectionable leakage. The roll 41 is preferably of the type adapted to yield locally at its periphery to accommodate local variations in the web thickness. For this purpose, the roll 41 may have a resilient surface or be of the multiple ring type disclosed in my Patent No. 3,040,553 dated June 26, 1962.

The lower rolls 39 and 40 are hollow cylinders and are provided at their opposite'ends with hollow trunnions extending loosely through the opposing end plates 19 and 20. More particulary, the -rolls 39 and 40 are provided at one end with respective hollow trunnions 39a and 40a (FIG. 3) extending loosely through end plate 20 in the manner illustracted in FIG. 4, where plate 20 is shown with an opening 42 through which trunnion 39a extends with a clearance. The respective passages 39b and 40b in these trunnions communicate with the interiors of the corresponding hollow rolls, but at their outer ends these passages terminate within the trunnions as shown in FIG. 4 in the case of trunnion 39a. Adjacent their closed outer ends, the passages 39b and 40b open radially of these trunnions through radial ports 3% and 400, respectively.

The trunnion 39a extends from roll 39 through a seal- 2 ing means, shown generally at 43, and thence through a sub-housing 44 (FIGS. 1 and 4). Similarly, the trunnion 40a extends from roll 40 through a sealing means, shown generally at 45, and thence through a sub-housing 46. The rolls 39 and 40 are adapted to be driven in the same direction (clockwise as viewed in FIGS. 2 and 3) by a common drive shaft 48, as through gearing 49, 50 and 51 shown in FIG. 1. Flexible couplings (not shown) may be interposed between trunnions 39a40a andtheir respective driving gears 50-51, to permit slight radial movements of the rolls 39-40 incident to wearing of their seats 37-38.

As the sealing means and sub-housings for the respec tive trunnions 39a and 40a are essentially alike, only the sealing means 43 and sub-housing 44 for trunnion 39a will be described in detail, the corresponding parts of sealing means 45 and sub-housing 46 having the same reference numerals but with the subscript a.

The sealing means 43 comprises an annular member 52 loosely surrounding trunnion 39a and removably secured to end plate 20 by machine screws 53. This annular member 52 has circumferentially spaced, radial elements 54, 55 and 56 integrally joining the two end portions of member 52. At its inner end, the member 52 is recessed to receive a ring 58 surrounding trunnion 39a with a clearance. An O-ring 59 of sealing material is fitted in a circumferential groove in ring 58 and seals against the surrounding wall of member 52. At its inner end, the ring 58 opposes a ring 60 fitted quite closely around trunnion 39a and carrying an annular sealing element 61 which engages the opposing end face of ring 58 around the trunnion. An O-ring 62 of sealing material is fitted in the ring 60 and closely surrounds the trunnion 390. A compression spring 63 is coiled around the inner end portion of the trunnion and is compressed between the ring 60 and an external shoulder of the trunnion.

Thus, the spring 63 urges ring 60 outwardly to press the sealing element 61 againstt he opposing end face of ring 58. The external sealing of the trunnion is completed by the O-rings 59 and 62 and by a suitable gasket 57 interposed between end plate 29 and the annular member 52. v

The sub-housing 44 comprises a housing member 64 surrounding the trunnion 39a and having an external flange 65 at its inner end. The housing member 64 is releasably secured to the opposing outer end of annular member 52 by machine screws 66 extending loosely through flange 65 and threaded into member 52. A ring 66' contains an O-ring 67 closely surrounding trunnion 39a, the ring 66 being located in the housing member 64 at its open inner end. At its inner end, the ring 66' carries an annular sealing element 68 surrounding the trunnion and bearing against the outer face of a ring 69 located in a recess in the opposing end of annular member 52. An O-ring 70 is fitted in a circumferential groove in a circumferential groove in ring 72 and seals against the v surrounding wall of member 64. A ring 74 contains an O-ring 75 closely surrounding the trunnion and is provided at its outer end face with an annular sealing element 76 bearing against the inner face of ring 72. A spring 77 is coiled around the trunnion 39a and is compressed between the rings 66' and 74. Accordingly, the annular sealing elements 68 and 76 are pressed against the opposing end faces of rings 69 and 72, respectively; and sealing of the sub-housing chamber 71 is completed by the 0- rings 67, 70, 73.and 75.

It will be apparent that the spring-loaded sealing rings 60, 66' and 74 permit slight radial movements of roll 69 so that the roll remains in firm sealing engagement with its seat 37 despite wearing of the latter. It will also be apparent that the periphery of trunnion 39a is exposed through the gaps between the radial elements 54, 55 and 56, so that any leakage along the trunnion from the end plate opening 42 or from sub-housing chamber 71 can easily be detected.

Secured to the opposite end plate 19 of pressure seal 11 are trunnion sealing means 80 carrying a sub-housing 81 and trunnion sealing means 82 carrying a sub-housing 83 (FIG. 1). The corresponding hollow trunnions of rolls 39 and 40 are similar to the trunnions 39a and 40a except that they terminate in the chambers of the respective subhousings 81 and 83 into which the trunnion passages open. The sealing means 80 and 82 are similar to the sealing means 45 and 43, respectively; and the sub-housings 81 and'83 are similar to the sub-housings 46 and 44, respec tively, except that they are completely closed at their outer ends. Thus, the outer sealing rings 72 and 74 (FIG. 4) are unnecessary in the sub-housings 81 and 83.

Sub-housing 44 is provided with a bottom opening 78 (FIG. 6) leading from the chamber 71 into a pipe 84 connected to this sub-housing, as shown in FIG. 1. The sub-housings 46, 81 and 83 are provided with similar bottom openings (not shown) leading into pipes 85, 86 and 87, respectively, which are connected to the corresponding sub-housings. The pipes 86 and 87 are supplied with water or other cooling liquid under pressure, from a suitable source (not shown); and the pipes 84 and 85 serve for discharge of the liquid after it has cooled the rolls 39 and 40. Thus, the pipes 84-87, the corresponding sub-housings 44, 46, 81 and 83, and the corresponding sealing means 43, 45, 80 and.82, comprise means for circulating a cooling liquid through the cooling passages of the hollow rolls 39-40 and their trunnions.

As the rolls 39 and 40 are rotated by their driving means 48-51, the web F is drawn upwardly from inlet 22 through the nip between rolls 40 and 41 (FIG. 3) and passes into the treating vessel 10 by way of outlet 23. The fluid pressure in housing chamber 14 presses the rolls 39-40 against their respective seats 37 and 38 and also presses the upper roll 41 against the rolls 39 and 40, as previously described, whereby the housing chamber 14 is effectively sealed against escape of pressure fluid from the vessel 10. Con densation of the pressure fluid (steam) on the walls of chamber 14 is prevented by the aforementioned heating effect of the steam passing through the heating passages 26, 27 and 28. At the same time, pressure fluid in chamber 14 is condensed on the outer cylindrical surfaces of the rolls 39 and 40 due to cooling of the latter by the cooling liquid circulated through these rolls. This cooling action serves to remove heat created by friction on the moving rolls; and the condensate formed on their outer surfaces acts as a lubricant and promotes the sealing effect.

It will be understood that the pressure vessel 10 has an outlet passage (not shown) through which the treated web F is discharged, and this outlet passage may be sealed against escape of pressure fluid by a pressure seal similar in principle to the pressure seal 11.

I claim:

1. In combination with a pressure vessel for treating material in the form of a web, a housing forming a chamber having a first opening communicating with atmosphere and having a second opening communicating with the interior of the pressure vessel, said openings forming a-- web inlet and a web outlet for passage of the web through the housing chamber between said vessel interior and atmosphere, a pair of roll seats fixed in said chamber and extending along opposite sides, respectively, of said first opening, a pair of rolls seated on the respective seats and extending in substantially parallel relation toeach other in position to receive the web between said rolls, one of said seated rolls being positioned to engage its periphery with one side of the web passing through said chamber, a yieldable roll in the chamber extending sub stantially parallel to said seated rolls and straddling them imposition to have the periphery of the yieldable roll urged against the peripheries of the seated rolls by fluid pressure from said second opening, whereby the yieldable roll is adapted to press the web against said one seated roll and accommodate different thicknesses of the web while coacting with the seated rolls to maintain a pressure seal bet-ween said housing openings, each said seated roll being adapted to rotate while urged against its seat, at least one of said sea-ted rolls being hollow to provide therein a cooling passage extending lengthwise of the roll, and means for lubricating and cooling the seat for said hollow roll, said last means including means for circulating a cooling liquid through said cooling passage, whereby vapor from said pressure vessel is condensed on the periphery of said hollow roll.

2. The combination defined in claim 1, in which the housing contains heating passages closed from the chamber and extending generally parallel to said rolls and along opposite sides of said' second opening, said heating passages having inlets and outlets for a heating medium to prevent said vapor from condensing on the walls of said chamber.

3. In combination with a pressure vessel for treating material in the form of a web, a housing forming a chamber having a first opening communicating with atmosphere and having a second opening communicating with the interior of the pressure vessel, said openings forming a web inlet and a web outlet for passage of the web through the housing chamber between said vessel interior and atmosphere, a pair of roll seats fixed in said chamber and extending along opposite sides, respectively, of said first opening, a pair of rolls seated on the respective seats and extending in substantially parallel relation to each other in position to receive the web between said rolls, one of said seated rolls being positioned to engage its periphery with one side of the web passing through said chamber, a yieldable roll in the chamber ext-ending substantially parallel to said seated rolls and straddling them in position to have the periphery of the yieldable roll urged against the peripheries of the seated rolls by fluid pressure from said second opening, whereby the yieldable -roll is adapted to press the web against said one seated roll and accommodate different thicknesses of the web while coacting with the seated rolls to maintain a pressure seal between said housing openings, at least one of said seated rolls being hollow to provide therein a cooling passage extending lengthwise of the roll, said hollow roll having hollow trunnions extending from the ends thereof and communicating with the interior of said hollow roll, the housing including end walls having openings through which the respective trunnions extend, the combination comprising also means sealing each of said end wall openings around the corresponding trunnion, a sub-housing into which each trunnion extends from the corresponding sealing means, each sub-housing having a sealed chamber 7 into which the interior of the corresponding hollow trunnion opens, a cooling liquid supply pipe leading to said sealed chamber of one sub-housing, and a cooling liquid discharge pipe leading from said sealed chamber of the other sub-housing.

References Cited by the Examiner UNITED STATES PATENTS 1,170,228 2/1916 Elliott 68-5 1,595,240 8/1926 Minton. 1,633,121 6/1927 Minton 34-242 Fahringer 68-5 Higginbottom 68-5 Rust 68-5 X Healey 68-22 Nakaguchi 68-5 Frank 34-242 X FOREIGN PATENTS Switzerland.

10 IRVING BUNEVICH, Primary Examiner. 

1. IN COMBINATION WITH A PRESSURE VESSEL FOR TREATING MATERIAL IN THE FORM OF A WEB, A HOUSING FORMING A CHAMBER HAVING A FIRST OPENING COMMUNICATING WITH ATMOSPHERE AND HAVING A SECOND OPENING COMMUNICATING WITH THE INTERIOR OF THE PRESSURE VESSEL, SAID OPENINGS FORMING A WEB INLET AND A WEB OUTLET FOR PASSAGE OF THE WEB THROUGH THE HOUSING CHAMBER BETWEEN SAID VESSEL INTERIOR AND ATMOSPHERE, A PAIR OF ROLL SEATS FIXED IN SAID CHAMBER AND EXTENDING ALONG OPPOSITE SIDES, RESPECTIVELY, OF SAID FIRST OPENING, A PAIR OF ROLLS SEATED ON THE RESPECTIVE SEATS AND EXTENDING IN SUBSTANTIALLY PARALLEL RELATION TO EACH OTHER IN POSITION TO RECEIVE THE WEB BETWEEN SAID ROLLS ONE OF SAID SEATED ROLLS BEING POSITIONED TO ENGAGE ITS PERIPHERY WITH ONE SIDE OF THE WEB PASSING THROUGH SAID SAID CHAMBER, A YIELDABLE ROLL IN THE CHAMBER EXTENDING SUBSTANTIALLY PARALLEL TO SAID SEATED ROLLS AND STRADDLING THEM IN POSITION TO HAVE THE PERIPHERY OF THE YIELDABLE ROLL URGED AGAINST THE PERPHERIES OF THE SEATED ROLLS BY FLUID PRESSURE FROM SAID SECOND OPENING, WHEREBY THE YIELDABLE ROLL IS ADAPTED TO PRESS THE WEB AGAINST SAID ONE SEATED ROLL AND ACCOMMODATE DIFFERENT THICKNESS OF THE WEB WHILE COATING WITH THE SEATED ROLLS TO MAINTAIN A PRESSURE SEAT BETWEEN SAID HOUSING OPENING, EACH SEATED ROLL BEING ADAPTED TO ROTATE WHILE URGED AGAINST ITS SEAT, AT LEAST ONE OF SAID SEATED ROLLS BEING HOLLOW TO PROVIDE THEREIN A COOLING PASSAGE EXTENDING LENGTHWISE OF THE ROLL, AND MEANS FOR LUBRICATING AND COOLING THE SEAT FOR SAID HOLLOW ROLL, SAID LAST MEANS INCLUDING MEANS FOR CIRCULATING A COOLING LIQUID THROUGH SAID COOLING PASSAGE, WHEREBY VAPOR FROM PRESSURE VESSEL IS CONDENSED ON THE PERIPHERY OF SAID HOLLOW ROLL. 